the 1042 is a window comparator. You could configure a couple of op amps to do that.
Frankly, I don't like that design for several reasons. Basically, it only charges the main battery when the wind speed is in a specific range (dependent on the motor and blade design). Why not use a SMPS to keep the voltage in a specific range and use a comparator to test for over voltage (charged)? that would make the charger more effective. There may well be charger chips that could do the job. Also, having 2 different batteries seems kind of odd. There ought be a design that eliminates the need.
Isn't there a missing connection on the schematic. I don't see how the nicad gets charged.